As the elderly population of the United States grows, identifying determinants of aging trajectories is of heightened importance. This project investigates the effect of immigration on the trajectories of health, disability, living arrangemens, and well-being of the native-born elderly age 75 and up. Fully 22 percent of health service workers are foreign born; in some states the fraction exceeds 50 percent. By expanding the pool of caretakers, inflows of foreign-born workers may affect the access to, cost, and quality of in-home or institutional care for the elderly. Immigration may also encourage substitution from informal family care to professional care for the elderly, and may allow the elderly to purchase support services such as house cleaning or gardening that allow them to age in place longer. The care-taking and living situations of the elderly, in turn, may have profound implications for their morbidity, mortality, and subjective well-being, especially among those who cannot manage the activities of daily living on their own. The specific aims of the project are as follow: (1) To investigate the link between immigrant concentrations in local areas and living arrangements of the native born elderly. Are immigrant-exposed elderly individuals more likely to age-in-place, less likely to live with or near their own children, or less likely to live in an institutional setting? (2) To investigate the link between immigrant concentrations in local areas and care-taking arrangements of the native born elderly. Does immigrant labor substitute for informal family care-taking arrangements among those who need assistance? (3) To investigate the link between immigrant concentrations in local areas and the health trajectories, disability, and mortality of the elderly. Conditional on baseline health, does aging in an area with many immigrants affect limitations to activities of daily living, morbidity, the management of chronic disease, or the probability of death? If so, what are the mechanisms? (4) To investigate the link between the outcomes in Specific Aims 1 through 3 and the subjective well-being of the elderly. The project incorporates secondary analysis of four large national datasets. It uses an innovative methodology to account for endogenous migration of both native born elderly and immigrants. This allows the causal impact of immigration on the health and caretaking arrangements of the elderly to be isolated. High rates of immigration in recent decades may transform the aging experiences of the native born elderly, but the impacts of immigration on the native elderly have received little attention. As the nation debates admissions policies for immigrants and as baby boomers reach retirement age, the role of immigrants in the provision of health and other services to the elderly has direct and urgent policy relevance.